1. Field of the Invention
This invention relates generally to an apparatus for applying solder resist, and more particularly to a method and apparatus for applying a solder resist to miniature connector structures without need for special masking.
2. Description Of The Prior Art
Miniaturization of electronic components has created a demand for a tremendous quantity of miniature contact, terminal and connector structures. The demand for such miniature contact and connector structures has in turn created a demand for new techniques and new equipment for soldering and treating miniature electrical connectors with solder resistant coatings.
In particular, numerous problems have arisen in soldering miniature connectors and especially in confining solder to appropriate areas of a miniature connector while preventing it from flowing through all portions of the connector and thereby destroying or imparing the mechanical functioning of the connector. More specifically many miniature connectors have spring arms and the like which are designed to frictionally grip portions of electronic components and therefore must be free to move. However the small size of such connectors produces a strong wicking or capillary action in any melted solder which is applied to the connector, so that solder is often drawn throughout the connector by the wicking action, soldering the spring arms together and preventing them from functioning properly. As a result it is often necessary to apply a solder resist, or material which resists the flow of solder, to various portions of a miniature connector to combat the wicking or capillary action. Naturally the resist material must be applied with great care so that it does not touch areas of the connector where solder should adhere. To prevent application of the resist material to such areas, it has often been the practice to mask certain areas of the connector. However the small size of miniature connectors makes accurate masking a virtual impossibility unless costly and time consuming efforts are made in this regard. As a result there is a great need at the present time for a machine and a technique which permits precise and rapid application of a solder resist to miniature connectors without need for special masking.